The invention relates to an inflatable gas bag for restraining systems in vehicles. In a vehicle collision such a gas bag is inflated within a few milliseconds and serves to protect the vehicle occupant as impact protective cushion. For optimum protection of the vehicle occupant the ejection direction of the gas bag on unfolding should be directed substantially to the centre of the sitting position so that the occupant penetrates centrally into the impact protective cushion. Depending on the vehicle type, it may be necessary to make the shape of the gas bag asymmetrical in the completely inflated state. The deviation of the ejection direction on unfolding of the gas bag from the ideal ejection direction pointing to the centre of the sitting position due to asymmetry of the gas bag can fundamentally be compensated by a suitable installation position of the entire gas bag restraining system in the vehicle. However, the configuration of the vehicle interior permits only limited changes of the orientation of the gas bag restraining system.